Table 3.

Institutional Heparin Dosing Protocol Based on the Antifactor Xa Assay

	Indication
	Venous Thrombosis	Cardiac	CNS or Postpartum Thrombosis
Starting dose
Bolus	80 U/kg	70 U/kg	None
Starting rate	18 U/kg/h	15 U/kg/h	12 U/kg/h
Monitoring	Check anti-Xa assay 6 h after UFH initiation
Dose adjustments based on the anti-Xa assay result, U/mL
<0.2	Bolus: 30 U/kg		Bolus: None
	Infusion: Increase rate by 3 U/kg/h		Infusion: Increase rate by 3 U/kg/h
	Monitoring: Repeat anti-Xa in 6 h		Monitoring: Repeat anti-Xa in 6 h
0.2-0.29	Bolus: 30 U/kg		Bolus: None
	Infusion: Increase rate by 3 U/kg/h		Infusion: Increase rate by 2 U/kg/h
	Monitoring: Repeat anti-Xa in 6 h		Monitoring: Repeat anti-Xa in 6 h
0.3-0.7	No change
	Monitoring: Repeat anti-Xa with next day’s labs
0.71-0.8	Infusion: Decrease rate by 1 U/kg/h
	Monitoring: Repeat anti-Xa in 6 h
0.81-0.99	Infusion: Decrease rate by 2 U/kg/h
	Monitoring: Repeat anti-Xa in 6 h
≥1	Infusion: Hold for 1 h; at restart, decrease rate by 2 U/kg/h
	Monitoring: Repeat anti-Xa in 6 h

Anti-Xa, antifactory Xa; CNS, central nervous system; UFH, unfractionated heparin.